
Statistics for Data Science II Quiz 2: 16 March 2025 (January 2025 term)
The IIT Madras BS Statistics for Data Science II (Stats 2) Quiz 2 paper sat on 16 Mar 2025, in the January 2025 term: 16 questions for 40 marks in 120 minutes. Every question is below with its answer. Take it as a timed mock test to be marked, or read it through first.
- 16
- 40
- 120 min
- 7
- 2
- 7
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Question 2
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Question 3
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Question 4
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Question 5
Wires produced from a factory have a mean breaking strength of 50 kilograms with a standard deviation of 4 kilograms. In a statistical study of breaking strength of these wires, suppose the sample size is increased from 81 to 144.
Based on the above data, answer the given subquestions.
How does the expected value of the sample mean change?
The expected value decreases.
The expected value increases.
The expected value remains the same.
The expected value fluctuates randomly.
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Correct answer
The expected value remains the same.
Question 6
Wires produced from a factory have a mean breaking strength of 50 kilograms with a standard deviation of 4 kilograms. In a statistical study of breaking strength of these wires, suppose the sample size is increased from 81 to 144.
Based on the above data, answer the given subquestions.
How does the variance of the sample mean change?
Variance is reduced from 0.049 to 0.027
Variance is reduced from 0.198 to 0.111
Variance is increased from 0.111 to 0.198
Variance remains the same.
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Correct answer
Variance is reduced from 0.198 to 0.111
Question 7
Based on the above data, answer the given subquestions.
Find the value of E[X]. Enter the answer correct to two decimal places
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Correct answer: 0.42 (accepted within ±0.03)
Question 8
Based on the above data, answer the given subquestions.
What is the value of Var(X)? Enter the answer correct to two decimal places.
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Correct answer: 0.08 (accepted within ±0.03)
Question 9
Based on the above data, answer the given subquestions.
Find the value of k.
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Correct answer: 4
Question 10
Based on the above data, answer the given subquestions.
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Question 11
Based on the above data, answer the given subquestions.
Which of the following option(s) is(are) correct ?
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Question 12
Based on the above data, answer the given subquestions.
Using Chebyshev’s inequality, find a lower bound for P(|Y −0.5| < 0.6). Enter the answer correct to three decimal places.
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Correct answer: 0.977 (accepted within ±0.004)
Question 13
Based on the above data, answer the given subquestions.
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Correct answer: 0.75 (accepted within ±0.03)
Question 14
Based on the above data, answer the given subquestions.
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Correct answer: 0
Question 15
Based on the above data, answer the given subquestions.
Which of the following options is an acceptable approximate model for S as per the Central Limit Theorem?
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Question 16
Based on the above data, answer the given subquestions.
Using the Central Limit Theorem, find an approximate probability that the total number of heads, S, lies between 48 and 52 heads. Enter the answer correct to two decimal places.
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Correct answer: 0.31 (accepted within ±0.03)